Antitampering meter



May 28, 1935- w. c. WAGNER ET AL 2,002,968

ANTITAMPERING METER Filed Aug. 16, 1933 2 Sheets-Shea?l l 22 A fs 22 I/3 Q) @D @(5) @D @D @D l2 3 lll 1,//0

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May 28, 1935. w. c. WAGNER |=:r AL 2,002,968

ANTITAMPERING METER Filed- Aug. 16,1953 2 sheets-sheet 2 W @aww/K 1 yf:UNlTsofgSTATES.

Patented Mayl `28, 1935 ricainsl PATENT l OFFICE: f

ANTITAMPERING METER Walter C. 'Wagnen Ardmore,` Pa'., and George Y B.Schleicher, Clementon, N. 'J'.

Application Angustia, 1933, serial No. y685,403

6 Claims.

.""Ihis invention relates to integrating electrical meters, particularlywatthour meters, and itsobjectis to make more ydiiiicult.interferencewith Aregi stration by unauthorized persons. The inf .5 vention coversnew and novel means of; protec tion, against the unauthorized stopping.of theY meter disk while load is being supplied, and against reverseoperation of the meter registen The principles involved are capable ofapplica# tion-invariousways, and a number of `means of accomplishing theresults are given as. examples of the principles involved rather than inthe form of specic construotionldetails. Y

Fig. 2 is a diagrammaticand somewhat .sche-v matic view illustrating adouble shell `case with low voltage, obtained from the secondary of asmall transformer, applied between the two parts A of the shell, and arelay to open the load circuit.

, rlhe gure showsthe relay arranged to open both sidesfo'fv the line.

Fig. 3 `is a similar View .with line voltage be?v tween the'shellsarranged to blow a' fuse in the potential. circuit ofthe meter when themeter case is drilled.

' Fig. 4 isthe sameas Fig. 3 except that the'fuse within the meter openstheload circuit.

Fig, 5 illustrates anoverrunning ratchet mechanism operatedby a motorwhen the meter disk is stopped while load ,is supplied or when themethod of tampering consists of reversing the rotation of the meterdisk.

Fig. 6 is a View illustrating the electrical connections of Fig. 5.

Fig. 7 illustrates an alternative arrangement in place of the doublecover, and consists of insulating the internal moving and fixed parts ofthe meter from the base and cover.

Fig. 8 shows an alternative arrangement to Fig. 1, in that the meterpotential coil has been provided with taps so that it serves also as anauto-transformer for supplying the required low voltage.

In Figs. 2 to '7, inclusive, a standard potential coil i and a currentcoil 3 of an induction Watthour meter are arrangedA in operativerelation to disk 2 which drives register I3.

The relays of Figs. 1, 2, 6, or 8, may be arranged to close a circuitwhich would operateV any de-V sired device; for example, a flasher,buzzer, alarmA or light, or they may open the potentialcircuit of Vrthemeter to facilitate the, discovery ofthe tampering `due to theV absenceof registration. Contacts Hl are used-to close a circuit, andifV 5 thisfeature is not desired theseeontacts may be!N omitted; similarly, whencontacts Iiiare used contacts! l, which open a circuit, may be omittedand the connections changed accordingly if the interruptionof theserviceis not desired. BothY v10 v features maybe applied if desired.Resett'ing the A relay A-to normal requires the opening o fthcmeter, andis accomplished by lifting latch l2 which causes armature IU andcontacts Iitoassume their normal position. relay within the meter is.such that latch l2 lis inaccessible to authorized Ypersons .antextension of thelatch or a simple mechanical ,linkage (not shown) l maybead'ded.

A tampering practice against which protection is advantageous, consists`of the unauthorizedy stoppingl of the disk.v This is generally accom-Jplished by drilling a hole into the meter cover or' base .and insertinga wire4 or other obstruction` through the hole. A method of protecting ameter against this form of `tampering consists in providing the meterwitha metal inner or` outer shell. Fig. 2 shows such an arrangementusing an inner shell. The shell 2i is insulated at all points from thebase and cover 22, and a diflerence ofv potential obtainedV from lowvoltage transformer 4 is applied between the meter base and cover 22,'-and'the shell 2i. It is'apparent that 'in` attempting .to drill throughthe meterV cover'or base, the drill will close the circuit from 35 y l Ythe low-voltage winding 'of transformer vthrough f relay coil 9 causingarmature It) to open contacts Hrwhich are then held in the open positionby latch I2. The secondary voltage is advanta-` geously chosen of amagnitude so that even under .i0 favorable conditions it cannot create ahazard for the tamperer, as, for example, 10 volts. It is apparent thatthe meter potential coilV and its core have the characteristics of theprimary of va transformer, and hence the addition oi an insulated lowvoltage winding to the'potentialcoil f permits the elimination of theseparate low-voltf age transformer. Fig. l` shows this arrange--V ment.

The'use of the metal shell is not limited to 5 the operation of a relay.Such a shell arranged in accordance with this invention may be used toblow a small fuse 23, Fig. 3,. in the potential circuit of the meter,thus causing the meter to stop; or the drilling of the cover may blow aIf the position ofVV theV 15] larger fuse 23, Fig. 4, arranged Withinthe meter structure to interrupt the load circuit.

The same principle, applied in a diierent Way, is adaptable to somemeters by insulating the grid ZIa, which supports the meter elementincluding parts I, 2, 3 and I3 from the meter base 22, at all points 23at .which it is supported. In` this case the drilling of the cover 22and the insertion of a wire will cause a relay to operate, or to blow afuse within the meter either inthe potential circuit or in the loadcircuit Vas soon as the wire closes the circuit between the outer shelland the meter grid. Anexample Vof this arrangement is shown in Fig. 7.

An alternative means ofvprotecting the meter against the stopping of thedisk is shown in Figs. y

5 and 6 which utilize an overrunning ratchet for closing a contact tooperate'a relay.` In Fig. 5,* Ythe meter consists of potential coil I,disk .2, cnr` rent coil 3, and register I3. Attached to a shaft of thedial train is a ratchetv wheel I4; a pawl or `pawls I5 are attachedl toa wheel,disk o r other means of support I 6 which is driven throughv Yportionately to the speed of the meter disk under normal conditions, butif meter disk 2Y is stopped or reversed while load is being suppliedmotor I8 will drive pawl I5 against ratchet wheel I4. Ratchet wheel I4is attached to shaft I9 by means of a thread on shaft I9. Motor I8,therefore,

will turn ratchetwheel III and move it laterally.

along shaft I9. 'Ihe lateral motion of wheel I4 will close contacts 20which in turn may operate a relay. In the arrangement shown, the motoris `connected in series with the current circuit so that it willoperatev only when load is being supplied. Fig. 6 shows typicalelectrical'connec- .tions for the mechanical arrangement whose principleis shown in Fig. 5.

It is apparent that a greatvariety of combinations. is possible inapplying the various ind ividual protective features to a particularmeter.

No attempt has been made toillustrate allpos-V sible combinations, or todescribe indetailuall of the various mechanical arrangements which willserve to utilize the principles disclosed in this y invention. It issubmitted that the invention re- 1 Weclaimz 1. An induction watthourmeter comprising the combination with its operating elements and theircircuits of a metal base and cover, an insulated metallic shell andhaving a voltage applied between said cover and said shell,r alow-voltage windingof a transformer for supplying said voltage andarelay interposed in said llow-voltage circuit. A Y

2. In the combination of claim 1, the relay havingl contacts arranged toremain in the closed position after the initial operation of saidrelay,`

and means for resetting, said relay to its original position.

e. 3. VIn the combination described in claim 1, the addition ofcontacts, the relay consisting of at least one coil and a latchedarmature, arranged so that the said armature operates at least one setof contacts.

4. In an induction watthour meter comprising the combination with itsoperating elements and their circuits, of the gear train which is drivenby the meter, contacts, a motor running at less speed than the geartrain, and an overrunning ratchet mechanism interposed between the geartrain and the motor, and of which a part isy threaded and closes saidcontactswhen the gear train is stopped.l

5. The combination described in claim 1 in which the difference ofpotential between the two component parts is .obtained from taps on thepotential coil of the meter.

6. In the combination described in claim 1 the difference of potentialbetween the two component parts being obtained from the low-voltagewinding of a. transformer, said transformer consisting of the potentialcoil of the meter for its primary winding and a secondary which is anadditional winding on thesame core as the potential coil of the meter.

W. C. WAGNER. GEORGE B. sCHLErCHER.

